Commonly assigned, published European Patent Application No. 0 675 072 A1 discloses a valve assemblage useful for dispensing liquids from a collapsible container or a rigid, vented container. At the bottom of the container, a first valve is installed in the spout of the container, the first valve assembly including a moveable, spring-biased piston which normally prevents flow of liquid from the container. An associated apparatus, such as a photographic processor into which the liquid is to be dispensed, includes a second valve assembly having a probe member which engages the piston of the first valve assembly to move the piston to a position which permits flow. As the first valve assembly is opened by the probe member, the second valve assembly also opens, thus establishing a flow path for liquid from the container into the associated apparatus.
As the associated apparatus operates, the liquid drains from the container. It would be desirable to provide a simple means for detecting and signaling a low liquid level within the container to enable an operator of the associated apparatus to replace the container in a timely fashion. Various systems are known for detecting liquid level in a vessel, such as those shown in U.S. Pat. Nos. 4,014,010 and 4,714,176. In copending U.S. patent application Ser. No. 08/671,459 entitled "Apparatus for Detecting Low Liquid in Bottom Draining Container", filed Jun. 27, 1996, there is disclosed a system for detecting low liquid level in a bottom draining container. In this copending application a float is used in combination with a beam of radiation to detect low level in the container in response to the position of the float. While the product works very well, a problem has been found in that occasionally the float may stick in position and thereby prevent proper operation of the detection system. In particular, surface tension between the engaging surface and the stop in combination with the surrounding liquid provides a surface tension such that occasionally the float will stick and cause misreadings.
Applicants have solved the problem of the float sticking by providing an improved float member for use in the valve assembly associated with the container.